1. Field of the Invention
The present invention generally relates to screen brightness control, and in particular to a control method for a screen-illuminating panel.
2. Description of the Related Art
Backlit LCD displays have been widely used in handy or laptop computers and small, battery-powered electronic devices. To further improve the LCD screen's readability, there have been proposed backlit LCD displays which are capable of automatically adjusting their brightness depending on ambient illumination.
In Japanese Patent Unexamined Publication No. 5-265401, a backlit LCD system is provided with a photo sensor and a brightness controller. The brightness controller calculates the optimal level of brightness based on illumination data received from the photo sensor, and then controls the drive current supplied to the backlighting panel so that the calculated optimal brightness is obtained on the LCD screen.
A backlit LCD display improves the LCD screen's readability but draws more power than an ordinary LCD display does. Therefore, it is desirable to be able to reduce power consumption, especially in the case of a battery-powered device such as a mobile telephone terminal.